1. Field of the Invention
This invention relates to electrical receptacles and particularly to pre-wired electrical receptacles.
2. Description of the Prior Art
Electrical receptacles have been used for years in homes, offices and industrial locations to deliver electricity to various equipment and appliances. Over the years, the design of the receptacle has become standardized. Essentially, it is an ovular device that has an insulated face that projects forward from an electrical box. The face typically provides two outlets that can be used to plug in appliances, or other equipment.
Receptacles are wired in a building's electrical circuits. Typically, receptacles have two pairs of screws attached to the sides of the receptacle. One pair is used to connect the “hot” leg and the other pair connects the neutral wire. The two pairs of screws allow receptacles to be daisy-chained together. In this way, many receptacles can be connected to one circuit. Moreover, the screws connect to a metal buss that can be divided into two distinct zones. This allows the electrician to wire the top outlet on one circuit and the bottom outlet on a separate circuit. For example, it allows one outlet to be fed by a switch so that it can be energized remotely, while the other outlet can be continuously energized.
Modern receptacles also have gripping teeth that allow a worker to insert a stripped wire into the back of the receptacle. In this way, wiring can be done faster. It has been noted, however, that the gripping teeth on the receptacles do not always hold and can loosen the connection overtime (due to repeated heating and cooling cycles of the wiring). As a result, most professionals do not use the gripping teeth in wiring receptacles. This means that the wires must be stripped and bent to fit under the screws, the screws must be tightened and then, typically, a piece of electrical tape is placed around the sides of the receptacle to reduce the hazard of electrical shock due to the exposed electrical parts.
Considering that even a relatively small house can have 30 individual receptacles—and business can have hundreds, the wiring process takes a significant amount of time. Moreover, it requires some skill to ensure that the wires are attached properly to the screws and they are properly tightened.
Several attempts have been made to make this process simpler. U.S. patents show specially designed boxes that are simple to wire. Specially made receptacles are then plugged into the pre-wired busses in these boxes. These devices eliminate the need for the time-consuming wiring of each receptacle. However, they have several drawbacks. First, their use would require a complete shift in modern wiring techniques. Boxes would have to be replaced and wired, new receptacles have to be obtained, and workers would have to be retrained in their use. Moreover, the cost of such equipment may be considerably higher than the equipment presently available.
FIGS. 1 and 2 show the prior art receptacle. FIG. 1 is a top view of a typical duplex type receptacle 100. The receptacle has a body 102, mounting ears 103 and mounting screws 104. In most cases, wiring of the receptacle is one by wrapping the skinned wire over the attachment screws 105. In most cases, two sets of screws 105 are provided. On one side of the receptacle, the “hot” wire is attached. On the other side, the “neutral” wire is connected. A ground wire is attached to screw 106 as well. If the circuit is daisy chained, an additional pair of wires is attached to the second set of screws 105. Otherwise, these screws must be tightened down. Once the wiring is complete, an electrician often wraps the body of the receptacle with electrical tape, to cover the screws and metal parts of the receptacle. This is done to prevent inadvertent contact with the “hot” metal parts of the receptacle. This process takes a considerable amount of time. When multiplied by the 50 or more receptacles in a modern house, or the hundreds of receptacles in a large building, the time spent on wiring receptacles is considerable.
Moreover, the task must be done correctly or else problems might ensue ranging from badly operating circuits to fires.